1. Field of the Invention
The present invention relates to a method and apparatus to identify a type of a disc in a disc drive, and more particularly, to a method and apparatus to identify a type of a recordable disc.
2. Description of the Related Art
There are various types of recordable discs, such as a recordable CD (compact disc) and a recordable DVD (digital versatile disc). The recordable DVDs can be divided into DVD−R/+R type discs, i.e., one-time recordable discs on which data can be recorded only one-time, and DVD−RW/DVD+RW type discs, i.e., re-recordable discs on which data can be recorded several times.
Although the shapes of the above-mentioned discs are the same regardless of the types of the discs, their physical disc formats are different according to the types of the discs. That is, a wobble is formed on one side or both sides of the discs, having a frequency of 140 KHz in the case of DVD−R/RW and a frequency of 817 KHz in the case of DVD+R/RW. Further, while the wobble of a DVD−R/RW is formed such that LPPs (Land Pre Pits) are formed in a land area, the wobble of a DVD+R/RW disc is formed using a phase modulation method.
In order to drive various types of discs having different physical formats in the same disc drive, the disc drive must be able to set operational conditions adequate to the physical format of a disc during a lead-in time period for the disc. The setting of the operational conditions is for normally reading data from or writing data to the disc. Setting a servo gain to stabilize servo operations is an example of setting the operational conditions of the disc drive. In order to set the operational conditions, the type of the disc must be correctly identified.
In a conventional method of identifying a type of a disc, the disc type is identified on the basis of an ID (identification) code recorded in a lead-in area of the disc. That is, after the operational conditions of a disc drive are set to read the ID code, the disc type is identified using the ID code recorded in the lead-in area and if the currently set operational conditions are adequate to the identified disc type, the lead-in operation for the disc is complete.
However, if the operational conditions of the disc drive are not adequate to the disc type, the disc drive must retry the setting of the operational conditions adequately to the disc type in order to identify that disc type. Accordingly, where the operational conditions of the disc drive are not adequate to the disc type to be identified, the lead-in operation is inefficiently performed.